He said he has witnessed what he believes to be serious miscarriages of justice and felt it was in the "public interest" that he speak out.

The serving officer said: "There appears to be an apathy from the CPS when prosecuting cases where Asian women are victims of honour-based violence.

"A conviction could lead to unrest in the affected community but if they discontinue a case they know most victims won't complain due to their vulnerability."

He told the paper he was prompted to speak publicly after the CPS dropped a forced marriage charge in a case because it said it was unable to locate the victim.

But Det Sgt Singh said he had written to the CPS saying the 27-year-old victim from south London would attend court.

The CPS instead said it would continue with the charges of false imprisonment and common assault and wrote to Det Sgt Singh apologising for not consulting him before dropping the charge.

Figures published by the CPS in September showed there were no successful prosecutions under a specific forced marriage offence in 2015/16, after its introduction in 2014.

However, the report showed there were 53 prosecutions "flagged" as forced marriage in 2015/16, with six in 10 of those leading to convictions. One defendant was convicted of breaching a forced marriage protection order.

A CPS spokesman said: "These crimes are among the most complex referred to the CPS by police and, as recent statistics show, all agencies involved have major challenges to overcome.

"We recognise that it can be very difficult for victims to come forward, report these crimes and maintain their support during a prosecution, due to the nature of the offences.

"Victims will often be reluctant to criminalise their families, and can feel isolated. The CPS recognises that honour-based violence and forced marriage are fields in which we need to improve our understanding, response and support to victims.

"We have recently launched a new Honour Based Violence and Forced Marriage Action Plan, which outlines the comprehensive steps we are taking to improve our performance in this area."